When a judge ruled this week that San Diego’s plan for financing an expanded convention center was legal, backers of the $520 million project quickly cheered the news, eager to reap the economic rewards they say will most certainly come with a much more spacious facility.

Their visions, though, of hundreds of thousands more well-heeled conventioneers spending money in San Diego hotels and restaurants will have to be deferred a while longer. Opponents say they will appeal the judge’s long-awaited ruling, likely postponing an anticipated 2017 opening of the expanded center by at least a year or longer.

The delay means some larger, more lucrative meeting groups may well bypass San Diego in the coming years, unwilling to wait out the legal wrangling over a hotelier-approved room tax that is the linchpin of the project’s financing plan. The prolonged uncertainty over the litigation comes at a time when the convention landscape is more competitive than it has ever been.

With cities eager to capitalize on what analysts say are the economic benefits of larger state-of-the art facilities, the number of well-positioned suitors eager for a share of convention business is far outstripping demand.

“The number of what you’d consider primary large conventions that are sought after because of their higher level spending is not expanding, so as the facilities expand and the options are greater for people, the pie is getting cut up smaller,” acknowledged Joe Terzi, CEO of the San Diego Tourism Authority, which handles bookings for most conventions at the center. “We already have conventions waiting on us that are going to make a decision right now. They’ve told us if you’re able to commit to 2018, ‘19, ‘20 we’ll come. Do we lose a lot in 2017? No, but if you don’t start selling the center for 2018 and beyond as soon as possible you’ll lose those conventions.”

San Diego’s biggest convention, Comic-Con, with more than 130,000 attendees, has previously been heavily courted by the cities of Los Angeles and Anaheim but organizers have since agreed to stay put through 2016. It’s unknown, though, how patient Comic-Con International will be if the expansion continues to be delayed. Spokesman David Glanzer said he did not want to comment on what might happen in the future.

Meanwhile, other large groups, which tend to schedule their meetings several years out, are weighing their options, given the uncertainty. Some, like the American College of Surgeons, say a delay will not keep them from returning, while the Society for Human Resource Management, last in San Diego in 2010, may back away from a possible date in 2018.

“We’re a space hog. We use every square inch of San Diego’s space, so we need the expansion to maintain the quality of the event,” said meetings manager Jennifer Wroniewicz, whose convention draws up to 18,000 attendees and generates more than 12,000 hotel room nights. “There are only a handful of cities where we can actually do our show, but San Diego is not the only city vying for 2018. It makes the most sense to go back there, but if they’re not going to be ready we can’t come back.”

Since 2000, meeting space across the country has grown by more than 30 percent, while attendance, which dipped sharply between 2008 and 2010, has increased by just 2 percent, according to the Center for Exhibition Industry Research.

“It’s a bit ironic that all four major California destinations that compete for national conventions — Anaheim, San Diego, Los Angeles and San Francisco — are in various stages of considering expansion of their convention facilities,” said Doug Ducate, who heads the center.

He noted, however, that given San Diego's desirable climate, a well-located convention center steps away from the Gaslamp Quarter and a healthy inventory of nearby hotels, the city frequently has an edge over its rivals.

Recognizing there is some risk for groups looking to book an expanded center in 2017 and beyond, Terzi said he’s been talking to the Convention Center Corp. board about offering options for breaking contracts if the project doesn’t come to pass.

San Diego’s 1.1 million-square-foot bayfront center, last expanded in 2001, would grow by 400,000 more square feet of exhibit, meeting and ballroom space under the current expansion plan. While the project already has been endorsed by San Diego Port Commissioners and the City Council, it still must pass muster with the California Coastal Commission.

Citizen activists have filed two lawsuits against the city over the plan, arguing that an already approved hotel tax of 1 percent to 3 percent is illegal because if should have been voted on by the general electorate, not the hotel owners. Attorney Cory Briggs, who is handling one of the suits, has pledged to appeal all the way to the state Supreme Court, a process that could take two years or longer.

What worries some project advocates is that San Diego, at least for a couple of years, will miss out on the estimated 250,000 additional convention and trade show attendees a year the city could realize each year with an expanded center. A consultant’s analysis prepared for the city in 2010 estimated that the added attendance would translate into $348.8 million in spending on lodging, meals and other expenses.

More worrisome are the escalating construction costs the city is facing with each year of delay, said Charles Black, San Diego’s project manager for the expansion. Each year it is delayed, expect a $13.5 million hike in construction and design costs, he said.

“A year-and-a-half delay, it’s not the end of the world but it does make it more difficult,” said Black. “And the lost revenues, you never replace those.”